Analysis of biomarker expression in severe endometriosis and determination of possibilities for targeted intraoperative imaging

Abstract Objective To evaluate the expression of biomarkers in endometriotic tissue in order to determine the most promising molecules for targeted intraoperative imaging. Methods Tissue samples were obtained from 18 patients with endometriosis. The intensity and pattern of expression of the following biomarkers were assessed by immunohistochemistry: C-X-C chemokine receptor type 4 (CXCR4), epithelial cell adhesion molecule (EpCAM), estrogen receptor (ER), folate receptor α (FR-α), hypoxia-inducible factor 1-α (HIF-1α), progesterone receptor (PR), and vascular endothelial growth factor A (VEGF-A). The Target Selection Criteria scoring system was used to select the most promising biomarkers for intraoperative imaging. Results Expression of CXCR4, EpCAM, ER, PR, and VEGF-A was scored as strong in endometriotic epithelium. Expression of FR-α was detected in 94.4% of samples, whereas HIF-1α was expressed in just 5.6% of samples. Of note, CXCR4, ER, and VEGF-A were also expressed in surrounding healthy tissue, thus reducing the target-to-background ratio. Conclusion Of the 7 biomarkers assessed in the present study, EpCAM, FR-α, and VEGF-A seem the most promising for targeted intraoperative imaging of endometriosis.